Esters of 4-chloro-omicron-toloxyacetic acid



Patented Aug. 11, 1953 7 2,648,701 ESTERS or 4-CHL0RI(l))-o-T0L0XYACETICLouis E. Begin, Midland, Mich., assignor to The vDow Chemical Company,Midland, Mich., a corporation of Delaware No Drawing.

Application September 18, 1951, Serial No. 247,190

Claims. (01. 260-473) 1 The present invention relates to esters of 4-chloro-o-toloxyacetic acid and is particularly concerned with compoundshaving the formula wherein n is an integer not greater than 3, and R.represents a member of the group consisting of alkyl and phenyl. Thesecompounds are adapted to be employed as modifiers in plasticcompositions; preservatives for paper, wood and cellulosic textiles; andplant growth control'materials.

The new esters are oily liquids, somewhat soluble in many organicsolvents, and substantially insoluble in water. These compounds arestable to light and air, not appreciably affected by carbon dioxide,noncorrosive to the skin of man and higher animals, and of lowvolatility.

The compounds may be prepared by reacting a molecular proportion of (1)4-chloro-o-toloxyacetic acid with (2) at least a molecular proportion ofa mono-ether of mono-, di-, or tripropylene glycol such asmethoxy-propanol, ethoxy propanol, propoxy-propanol, butoxy-propanol,hexoxy-propanol, nonyloxy-propanol, phenoxypropanol,methoxy-propoxy-propanol, ethoxypropoxy-propanol, propoxy-propoxypropanol, butoxy-propoxy-propanol, hexoxy-propoxy-propanol,nonyloxy-propoxy-propanol, phenoxypropoxy-propanol, methoxy-propoxypropoxypropanol, butoxy-propoxy-propoxy propanol,nonyloxy-propoxy-propoxy-propanol and phenoxy-prop'oxy-propoxy-propanol.Good yields are obtained when a small excess of ether-alcohol isemployed, and the water of reaction is removed as formed. The reactionis carried out in the presence of an esterification catalyst, such assulphuric acid or phenol sulphonic acid.

-In one method of carrying out the reaction, the 4-chloro-o-toloxyaceticacid, a small molecular excess of the propylene glycol mono-ether,'andthe catalyst are mixed together and heated for a period of time atatemperatureoffrom 80 to-150 C. The heating is carried out under reducedpressure to remove water of reaction to- The resulting mixture dividesinto aqueous and solvent layers. The solvent layer, which contains theester reaction product, is separated and washed several times withwater. The solvent is then removed by distillation under reducedpressure to obtain the desired ester compound.

In an alternative procedure, the reaction is carried out in awater-immiscible solvent, such as ethylene dichloride. The reactants andcatalyst are dispersed in the solvent and heated together for a periodof time at a temperature of from to C. A mixture of the solvent andwater of reaction is continuously distilled out of the reaction vessel,condensed, and the solvent recovered. Additional solvent isintroducedinto" the reaction zone as may be necessary. Upon completionof the reaction, the mixture maybe neutralized, as with dilute aqueoussodium oarbonate, and the solvent layer separated from the aqueous layerand washed several times with water. The solvent is then removed bydistillation under reduced pressure to obtain the ester product.

The mono, di-, and tripropylene glycol monoat a temperature of C. and apressure of 200* pounds per square inch. The mixed reaction product maythen be employed as the monoether starting material or the individualetheralcohols separated by subjecting the mixed reaction products tofractional distillation under reduced pressure.

The following examples illustrate the invention but are not to beconstrued as limiting the same: v

' Example 1 200.5 grams (1 mole) of 4-chloro-o-toloxyacetic acid, 1'77grams (1 mole) of isopropoxy-propoxypropanol (boiling at 204 C. at 760millimeters pressure), 250 milliliters of ethylene dichloride and 1milliliter of sulphuric acid were heated together for 4 hours at a pot'temperature of 103 C. The operation was carried out with continuousdistillation of ethylene dichloride together with the water of reactionasformed,

separation of the water, and recycling of ethylene dichloride. Uponcompletion of the reaction,

pared to a theoretical chlorine content of 9.96

percent.

Example 200.5 grams (1 mole) of 4-chloro-o-toloxyacetic acid, 206 grams(1 mole) of methoxypropoxy-propoxy-propanol (boiling at 247 C. at 760millimeters pressure), 200 milliliters of ethyl-- ene dichloride and lmilliliter of sulphuric acid' were heated together for 2 hours at a pottemperature of 105 C; The operation was. carried out with continuousdistillation of ethylene dichloride together with the water of reactionas formed','separation or the water, and recycling of ethylenedichloride. Upon completion of the re-.

action, the mixturewas neutralized with dilute aqueous sodium.carbonate. The solvent and aqueous layers were separated and the solventlayer washed with water.

Ercample 4 4078- grams (20.3- moles) 4-chloro-o-tol'oxyacetic acid,.3857 grams (20.3; moles) of butoxy-propoxy-propanol (boiling at 228 C,at

760 millimeters pressure), 2900 milliliters of ethylene dichloride and.milliliteraof sulphuric. acid were mixed together and heated over aperiod of about 2 hours at temperatures gradually increasing up to atemperature of 83 additionalv 10 milliliters of sulphuric acid wasthenadded to. the reaction zone and heating thereafter continued for about'7' hours at a head: temperature of from about 7'7 to853 C3. Theoperation. was carried: outwith continuous: distillation of ethylenedichloride together with the. water of reaction as formed, separationofithe water and recycling oi the ethylene dichloride. Upon completionof the reaction, the reaction mixture was neutralized withtriethanolamine and the ethylene dichloride thereafter removedby'di'stillation to obtain a butoxy-propoxyepropyl' The latter was aviscous'oil' having a refractive index n/D' 4-chloro-o-toloxyacetateproduct.

of 1.4868 at 25 C.

Example 5 2609 grams (18 moles) of 4-chloro-o-tolo'xyacetic acid, 3780grams (18 moles) of phenoxypropoxy-propanol (boiling at 285.7 C; at 760The ethylene di'chloride was then separated by distillation at reducedmillimeters pressure), 300 milliliters of ethylene dichloride and 10milliliters of sulphuric acid were mixed together and heated for about13 hours at a pot temperature of from about to C. The operation wascarried out with continuous distillation Methylene; dichloride togetherwith the water of reaction as formed, separation of the water andrecycling of the ethyl-I .en'e dichloride. Upon completion of thereaction,

the reaction mixture was neutralized with dilute aqueous SO'dflliIl"carbonate. The solvent and aqueous layers were then separated and thesolvent. layer. washed: several times with water. The ethylenedichloride was then removed by distillatiorr under reduced pressure toobtain a phenoxy-propoxy-propyl 4 chloro-o-toloxyacetate-product. Thelatter was a viscous oil having a refractive index n/D of 1.5302 at 25C.

Example 6 5086 grams (25.36? males)- as 4 chloro-o-toloxyacetic acid,4086 grams (-26.7- moles) of. a m-merl; polypropylene glycol butylether" (having-1 an.-

average molecular weight of 153 and containing '72 percent ofl-butoxy-2-propanol, 20 percent of butoxy-propoxy-propanol and 8 percentof the butyl ethers of triand higher polypropylne sly o and 39 ramsotfip enol su phopic acid were mixed together and-heated at atemperature-offrom about 91 to -1.2% C. and under. reduced pressuretodistillotfamixture- .01? Water th m x d po yp op ene lycol but l-etherout of the reaction. zone. The heatin Was car: ried out over a period ofabout 21 hours and at. a pressureot from 4.4. 5 .9 inches. The-mixed poyp o yle e glyc but l her a then s parated trom the accumulated mixture03 water. and. glycol butyl ether and. returned to the reaction zone.placed under reduced pressure and heated for 20 hours ata: pottemperature. of. about 130 C.

Upon completion of the reaction,. the mixture; was neutralized. with ammonium bicarbonate-and" filtered. As a e t of th above op rati na.

there. was obtained a.v mixed ester" product con.-

sisting. essentially of. the L-butoxy-2 ropylt b y p pel-xy- -'p py1-and-b ues pr -pe y p p y p opyl estersof or -o m x atetie a i Th s p uts a i licuidhwina refractive index n/D of 1.4.928 at-2.5 i

In a similar manner. other esters. of. 4.-chloroo-tol'oxyaceti'c acid.may be prepared of. which the following are representative.

T -p -z-p o y es er of lom-p l toloxyacetic acid by reactingtegethereFchloro-e o-toloxyaceti'c acid. and L-butox y-Z-propanolt The lL-phenoxy-Z-propyl ester of l chlore-o toloxyacetic acid by reactingtogether 4-,chlerofoe toloxy'aceti'c acid. and l.-phenoxy.- 2-propanol,

The butoxy-propoxy propoxypropyl ester or 4.-chloro-o tol'oxyaceti-cacidby' reacting. to ether h1 r 0 oetoloxyacetic acid and put oigyrprgi-x xy-propoxy-propanol.

P m-. y mop xy-pro i ester or:

4 -chlbro-o-toloxyacetib acid and. henoxyrpro POXY-DI'QIJOXy-propanoh I.claim:

I. An ester of i-cl loroeo-toloxya g .3 1g

the formula he in n air-integer notgreater than a gued The resulting.mixture was thereafter R represents a member of the group consisting ofalkyl and phenyl.

2. The butoxy-propoxy-propyl ester of 4-ch1oro-o-toloxyacetic acid.

3. The phenoxy-propoxy-propyl 4-ch1oro-o-toloxyacetic acid.

4.v The methoxy-propoxy-propoxy-propyl ester of 4-chloro-o-to1oxyaceticacid.

5. The isopropoxy-propoxy-propy1 ester of 4-ch1oro-o-to1oxyacetic acid.

LOUIS- E. BEGIN.

ester of 6 References Cited in the file of this patent UNITED STATESPATENTS OTHER REFERENCES Newman, Soil Sci. Soc. Am. Proc. 12, 217-2 1(1947).

1. AN ESTER OF 4-CHLORO-O-TOLOXYACETIC ACID OF THE FORMULA